题目内容：

All over the world the need for more laptops and computers increases each year. Networks have been part of our life. Probably everyone with a portable device (移动设备) has once logged on to a public WiFi network without paying for it, while they are having a coffee, on a train, in a shopping mall or at a hotel. However, is this kind of public WiFi network safe?

Some networks are better protected than others because encryption (加密) methods are used. Therefore, they are safer than others. But a survey in 2015 showed that more than 950 million records were not protected, including addresses, emails, birth dales, phone numbers, passwords and so on. These open WiFi networks are really not safe, because it is very easy for hackers to break into the operating system and get people's private information.

Most smartphones and laptops, by themselves, search and connect to WiFi networks. They usually prefer a network with a connection that has been used before. Hackers' devices are able to record these searches and look like the trusted WiFi networks. When these smartphones and laptops log on to the networks which are not real, hackers can easily steal their private information.

So next time, when we want to use our laptops or our smartphones in public places which offer free WiFi networks，please think it twice or take safe measures before using them.

1.We can learn from the passage that______.

A. not all the public WiFi networks are safe    B. none of the public WiFi networks is safe

C. in 2015 more than 950 million records were protected    D. there is no way to protect our private information

2.Hackers would probably get the following EXCEPT_______when we connect our laptops or smartphones to a public WiFi network.

A. our birth dates    B. our passwords

C. our phone numbers    D. our smartphones

3.Which of the following can be the best title of this passage?

A. Don't Use Public WiFi Networks    B. Why the Public WiFi Networks a Possible Danger

C. We Needn't Protect Our Private Information    D. Why Hackers Break into the Operating System